This invention relates to an improved structure for tape driving device, and particularly to an improved structure that uses idle wheel for driving the drive wheel in the cassette for leading tape driving device to motion.
The way of driving often used by the conventional tape driving device for being driven by the frictional force of drive wheel may include: (1) flat belt transmission (2) toothed belt transmission (3) motor direct drive (4) idle wheel drive.
Wherein flat belt transmission of drive wheel has advantage for simple structure, cheap cost but it is not an ideal way of drive because easy slip of belt will cause idle run. Though the way of drive by toothed belt may solve said problem of drive by flat belt, however it has to adopt toothed belt and belt wheel of special specification to increase the cost.
Though motor direct transmission of drive wheel is cheap cost and reliable for transmission, however owing to a large size of motor it is quite difficult for mounting motor close to drive wheel and it therefore causes the problem of space arrangement for cassette tape unit, further its dimensions are bigger than said ways of transmission.
Referring to idle wheel drive, it relates to idle wheel added between power output wheel of motor and tape drive wheel so it may achieve reliable transmission and cheap cost by direct transmission, and it also solves the problem of space arrangement found in direct transmission. Nevertheless, the structure for mounting members of transmission mechanism for idle wheel transmission, e.g. idle wheel, drive wheel and motor is quite complicated and difficult for assembly and therefore causes the problem of maintenance.